Automatic dosing devices for different yes of machines have since long been a target for manufactures. These devices shall be able to dose powder, liquid or other kinds of material from a container into a process. Therefore a various amount of dosing devices have been developed. Mostly these devices are developed for industrial use. They are therefore often quite expensive and/or complex constructions.
Recently there has been more focus on designing automatic dosing devices for household or at least cheaper appliances. Especially for laundry washing machines there is a large interest in achieving simple and reliable devices. Conventionally, such automatic dosing devices for dispensing a detergent into a washing tub has been proposed. The detergent is stored in a container and dispensed from a discharge at the outlet of the container. In order to avoid that vibrations causes detergent to fall out from the container at other occasions than when the detergent is to be dispensed, several proposed dosing devices have a discharge mechanism which is able to both dose and close the outlet.
U.S. Pat. No. 5,063,757 proposes a detergent dispenser with this kind of dosing and closing mechanism. The dispenser includes a detergent container with a lower discharge outlet from which stored detergent is discharged and a detergent fall preventing member displaced in the outlet in order to close the outlet when detergent is not dosed. The dosing is achieved by a helical coil/screw arranged is a discharge passageway. An agitating member is disposed in the detergent container in order to avoid clogging of the detergent. The helical coil or screw and the agitating member are rotated by an electric motor mounted together with the container. The container, with an outer and inner casing, is detachably mounted to the machine by claws.
Although the construction is developed to be detachably mounted inside a machine it has drawbacks. The detaching mechanism demands a careful handling by the user. The container and other parts also have to be clean to co-operate with the machine and in order to be fixed by the claws. Since the motor is placed with the container it is more expensive to have more than one dispenser for a machine. The container is also designed such that it makes it is difficult to fit in a space inside a washing machine in a proper way. Finally it is also important to create a construction as simple and cheap as possible, which means fewer and simpler parts than in this construction.
The present invention has been made with a view toward overcoming the above drawbacks of the prior art. A first-object of the present invention is therefore to provide a dosing screw unit for an automatic dosing device that avoids humidity leaking in through the passageway in which is the screw is arranged. In order to achieve that the unit has a closer that closes the passageway outlet when the screw is not dosing. A second object of the present invention is to provide a unit that avoids clogging of material inside the passageway and on the screw. In order to avoid that the unit has a cleaner that scratches of the clogged material. A third object of the present invention is to provide a unit that is easy for the user to switch and clean. In order to achieve that the unit is detachably attached to the automatic dosing unit. A fourth object of the present invention is to achieve a cheap unit that is simple to manufacture. In order to achieve that the unit has few simple parts of cheap, reliable materials. The dosing screw unit shall mainly be designed for an automatic dosing device for a laundry washing machine, but the principle idea shall be applicable for any kind of machine that requires an automatic dosing unit. The solution of this present invention is achieved according to the features disclosed in claim 1.
According to the present invention a screw unit for dosing (dispensing) material from a container into an outlet is provided. The unit is operated by an electric motor and comprises a dosing screw, a channel interacting with the screw, a sealing with a directer, a closer and an attacher which also works as a cleaner. All these parts will be described more thoroughly in the preferred embodiment. According to the above mentioned objects of the present invention all sealing parts are formed to achieve a cheap, reliable and effective unit for cleaning and sealing in an automatic dosing unit. Accordingly the sealing unit interacts with the dosing screw for best results.